This invention relates to a process for paraffin-olefin alkylation producing higher branched paraffins under strong, acid catalyzed conditions and in the presence of an aminoalkyladamantane hydrocarbon as a hydride transfer catalyst. The latter compound is preferably a surfactant in the acid system employed.
Alkylation of olefins by carbonium ions under strong acid conditions is a well-known process for producing a wide variety of useful hydrocarbon materials and particularly, gasoline blending components. For example, 2,2,4-trimethylpentane is a common blending component which is used for octane improvement of gasoline and it can be produced by alkylating isobutylene with t-butyl cations in sulfuric acid or liquid HF.
An example of an acid catalyzed reaction process is described in U.S. Pat. No. 3,231,633.
Hydrocarbon conversion processes employing novel Lewis acid systems are disclosed in U.S. Pat. Nos. 4,229,611 and 4,162,233, both assigned to Exxon Research and Engineering Company.
U.S. Pat. No. 3,671,598 describes a process for isomerizing saturated cyclic hydrocarbons under strong acid conditions in the presence of an adamantane hydrocarbon. However, no suggestion is made that it might be effective in paraffin-olefin alkylation nor that other specifically substituted adamantanes, particularly those with aminoalkyl substituents, might be more effective in increasing the rate of paraffin-olefin alkylation.
New methods for producing such alkylated paraffinic hydrocarbons useful as octane improvement agents are constantly being searched for in an effort to increase product quality and process efficiency. Improved processing should lower side reactions, leading to less catalyst consumption while increasing product quality (octane number), yield and reaction rate.